The present invention relates to a sealing ring for forming a pipe joint between two abutting pipe ends. More specifically, the sealing ring comprises a molded elastomer ring having an inner ring embedded therein. The axial ends of the sealing ring, which surrounds the butt joint of the pipe ends, extend into a sealing cavity formed in a recessed part, a flange or the like provided on the pipe ends and clamped together by screws. The axial ends are deformed when the two recessed parts or the like are clamped together and conform to the contour of the interior of the adjacent sealing cavity.
A device of this type is described in German Auslegeschrift No. 3,206,570. According to this document, a flange, at least one clamping element, and a recessed part, which can be clamped together by means of screws, are loosely slid onto each of two pipe ends. The flange and recessed part form between them a clamp recess into which the clamping element extends. The clamping element is support against the pipe end by a radially outwardly projecting clamping edge. The clamping element is overlapped by a clamping surface of the clamp recess with respect to a radially outward clamping edge. The clamping element projects axially outwardly from the clamp recess in such a way that an axial pressure exerted on the clamping element leads to an increase in the outside diameter and a decrease in the inside diameter of the clamping element. Each of the two recessed parts has a sealing cavity to accept the sealing ring, which cavities open toward the butt joing. The clamp recess which holds the clamping element is located in the aforesaid flanges and opens facing the butt joint. Both recessed parts can be clamped together by screws.
This pipe joint is particularly suited for high pressure use, and has already proven itself in practice. It has been shown, however, that under heavy loads, extrusion of the molded elastomer ring takes place in the region of its two outside annular edges which abut the outer surface areas of the two pipe ends. In these cases, sealing material flows into the tolerance gap between the recessed part and the pipe surface. It has further been shown that the assembly of this kind of pipe joint can lead to difficulties with regard to the mutual alignment of the pipe ends to be joined. Furthermore, the sealing ring is not suited for certain pipe surfaces.